This invention relates to a sports boot having a pivoted upper shell.
In a ski boot, the forward lean angle and the flex characteristic of an upper shell which is pivotally interconnected to a lower shell are important characteristics which should vary for skiers of different ability levels. Adjustability of the forward lean angle and the flex will allow one ski boot design to fit many different skiers, however, the adjustability should not be subject to inadvertent change while skiing.
Prior ski boots have used external hardware, generally mounted at the rear between the upper and lower shells, and incorporating spring means or resilient compressible material to control the flex between the upper and lower shells. The unflexed forward lean angle, or the maximum forward or rear angle during flexing, was often infinitely adjustable by movement of a stop such as a screw or sleeve. Unfortunately, such external hardware is exposed to the snow and freezing conditions, and creates an undesirable protrusion which can be dangerous. The adjustment mechanism could also inadvertently change during skiing.
To attempt to solve the problem of adopting one ski boot design to skiers of different ability levels, other ski boots have used internal mechanisms for controlling the forward lean angle and/or stiffness of the boot. Tension devices, located within the sole of the boot, have extended through channels to the upper shell to control the flex characteristics. The forward lean angle has been adjusted by stretching of the tension device, with the maximum forward lean angle being controlled by a sole located bumper which abutted the tension device. Unfortunately, this type of construction is unduly complex, increases assembly time, and adversely affects the ability of the ski boot to withstand extreme external forces. In still other ski boots, the stiffness adjustment has been accomplished by rotatable rods of varying cross section, housed within notches in the forward portion of a ski shell. Rotation of the rods would relatively block or open the space within the notches so as to control the stiffness of the shell. Such an arrangement does not allow adjustment of the forward lean angle, and is subject to inadvertent change during skiing.
Infinite adjustment of the forward lean angle and/or flex of an upper shell relative to a lower shell is not always desirable. While these adjustments should be different for skiers of different ability levels and/or strength, it seldom should be necessary to change the adjustment once selected until a particular skier has experienced a significant change in ability and/or strength.
Various entry systems have been devised for side or rear entry of a foot into the upper shell of a ski boot. Rear entry systems are less likely to interfere with the forward flexing action of an upper shell relative to a lower shell. Some rear entry doors, when closed, have been fixed with respect to the vamp shell, causing undue rubbing of the rear door against the skier's lower leg as the leg moves forwardly and rearwardly within the upper shell. To minimize stresses on the upper shell, the rear door has been of narrow width, thus making rear entry difficult. Furthermore, a vamp shell with a high back, sufficient to encompass the heel of a skier's foot, has been necessary to distribute to the vamp shell the forces which urge a skier's heel rearward during skiing. Unfortunately, such an arrangement requires the skier's foot to be lowered into the vamp shell, losing some advantages of a rear entry system, and making it difficult to provide adequate heel hold-down forces.